The man charged in an alleged plot to blow up Metrorail stations in Northern Virginia suggested ways to kill as many people as possible on the subway, wanted to battle U.S. troops in Afghanistan and Pakistan, and trained himself to fight, authorities alleged Thursday.

But Farooque Ahmed, 34, of Loudoun County never suggested any attacks inside the United States, and the plot to attack Metro was hatched by government operatives posing as terrorists, according to court records unsealed Thursday.

Ahmed told undercover FBI operatives who he thought were al-Qaeda terrorists that he was ready to martyr himself in battle, according to government documents. He had trained himself in martial arts, use of firearms, and knife and gun tactics, according to the documents, and he offered to teach those skills.

Ahmed, who also suggested that he purchase firearms for jihad, is charged with conspiring to support al-Qaeda in a plot to bomb Metro stations in Arlington County.

Ahmed faces a maximum prison term of 50 years if convicted. He has not entered a plea, and his attorneys from the federal public defender's service declined to comment.

The 12-page sworn affidavit in support of a warrant to search Ahmed's Ashburn home and bank accounts suggests that Ahmed became an active and willing participant in the plot, providing surveillance and reconnaissance and offering his opinion on how to generate the most casualties.

It paints a picture of a man preparing himself step by step for violence in the name of religion, buying rifles and a shotgun and practicing with them, and telling the FBI he would be ready to go "operational" after completing the hajj pilgrimage next month.

The affidavit, signed by FBI Special Agent Charles A. Dayoub, details a grim 10-month courtship that began in January, just two months after a shooting rampage in which Army Maj. Nidal Hasan is accused of killing 13 soldiers and contractors at the Army post at Fort Hood, Tex., and weeks after Umar Farouk Abdulmutallab allegedly sought to blow up an airliner over Detroit.

"AHMED stated that he wanted to kill as many military personnel as possible," Dayoub wrote. He "stated that between 4:00 p.m. and 5:00 p.m. would be the best time to stage an attack to cause the highest number of casualties."

Ahmed proposed an additional Metro station as a target, suggested locations to place bombs and even recommended that putting explosives in rolling suitcases instead of backpacks would be more effective, Dayoub wrote.

The papers detail clandestine meetings in hotels near Dulles International Airport at which Ahmed handed over thumb drives with surveillance video.

Dayoub wrote that Ahmed said he planned to complete the hajj pilgrimage to Saudi Arabia and then "conduct jihad" overseas. Dayoub said the FBI thinks that Ahmed had sought to buy guns for that purpose.